Interpretive Summary: Excessive soil erosion caused by agricultural drainage and flood control modifications to streams has degraded vital streamside habitat in agricultural watersheds. One type of conservation practice used to control excessive soil erosion in streamside habitats involves the use of an earthen dam and a metal drain pipe. Previous research has documented the erosion control effectiveness of this structure, but not its ecological impacts on amphibians and reptiles. These aquatic animals are of a concern to environmental scientists and the public worldwide because of the recent documentation of their declining populations. We evaluated amphibian and reptile communities in eroding streamside habitat and in four streamside habitat types created by this conservation practice. We found the greatest diversity and abundance of amphibians and reptiles occurred when installation of the conservation practice resulted in the creation of forest riparian wetlands. Our results suggest that this erosion control practice will create needed wetland habitats for amphibian and reptile communities and will protect agricultural fields from excessive erosion resulting from agricultural drainage and flood control in northern Mississippi.

Technical Abstract:
Riparian zones of streams in northern Mississippi have been impacted by agriculture, channelization, channel incision, and gully erosion. Gully erosion is the most severe form of erosion and has resulted in the fragmentation of remnant riparian zones within agricultural watersheds. One widely used conservation practice for controlling gully erosion is the installation of drop pipes. This practice involves placing earthen dams across eroding gullies and embedding a metal standpipe within the dam to convey water from the field to stream level. Installation of this structure halts gully erosion and results in the incidental replacement of eroding gullies with riparian habitats. Previous research evaluating gully erosion control structures have not considered the ecological impacts of these conservation practices on amphibians and reptile communities within impacted riparian zones. We compared amphibian and reptile communities among riparian habitats containing actively eroding gullies and four riparian habitat types created by drop pipe installation. Amphibians and reptiles were sampled from four gully erosion sites and four sites of each drop pipe created habitat type from 1994 to 1996. Amphibian and reptile diversity and abundance were the greatest in created riparian habitat types having mean habitat areas > 0.10 ha and mean pool volumes > 420 m3. Our results suggest the use of drop pipes to control gully erosion also creates needed riparian habitats for amphibian and reptile communities within impacted riparian zones of channelized streams in northern Mississippi. Additionally, altering the installation design will increase the ecological benefits resulting from this conservation practice.